Abstract
In this study, two distinct grades of commercial steel, DP600 and DP800, were thermo-mechanically tested relevant to mechanical behavior at five temperatures and two elongation rates. Some fundamental structural properties were also determined, including work (strain) hardening, strain rate sensitivity, and optimum ranges of forming temperatures. For both high-quality steels, tensile strength and flow stress noticeably decreased as work temperature increased. The maximum work hardening ratio for both strain rates was exhibited at 350 °C for DP600 and at 300 °C for DP800. Deformation velocity effects for the DP600 occurred at 500 °C, whereas they manifested at 400 and 500 °C for DP800. In the warm deep drawing tests, the optimum forming temperature for DP600 was 400 °C, while it was 450 °C for DP800, taking into account the deformation velocity of both steels. It was concluded that a controllable and feasible manufacturing alternative is possible using local warm forming.

Key words
advanced high-strength (AHSS), DP600, DP800, tensile test, warm forming

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